2021-04-03 15:19:41

by Pavel Skripkin

Subject: [PATCH] net: fix NULL ptr dereference in nl802154_del_llsec_key

syzbot reported NULL ptr dereference in nl802154_del_llsec_key()[1]
The problem was in case of info->attrs[NL802154_ATTR_SEC_KEY] == NULL.
nla_parse_nested_deprecated()[2] doesn't check this condition before calling
nla_len()[3]

Call Trace:
nla_len include/net/netlink.h:1148 [inline] [3]
nla_parse_nested_deprecated include/net/netlink.h:1231 [inline] [2]
nl802154_del_llsec_key+0x16d/0x320 net/ieee802154/nl802154.c:1595 [1]
genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:739
genl_family_rcv_msg net/netlink/genetlink.c:783 [inline]
genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:800

Reported-by: [email protected]
Signed-off-by: Pavel Skripkin <[email protected]>
---
net/ieee802154/nl802154.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ieee802154/nl802154.c b/net/ieee802154/nl802154.c
index 7c5a1aa5adb4..2f0a138bd5eb 100644
--- a/net/ieee802154/nl802154.c
+++ b/net/ieee802154/nl802154.c
@@ -1592,7 +1592,8 @@ static int nl802154_del_llsec_key(struct sk_buff *skb, struct genl_info *info)
struct nlattr *attrs[NL802154_KEY_ATTR_MAX + 1];
struct ieee802154_llsec_key_id id;

- if (nla_parse_nested_deprecated(attrs, NL802154_KEY_ATTR_MAX, info->attrs[NL802154_ATTR_SEC_KEY], nl802154_key_policy, info->extack))
+ if (!info->attrs[NL802154_ATTR_SEC_KEY] ||
+ nla_parse_nested_deprecated(attrs, NL802154_KEY_ATTR_MAX, info->attrs[NL802154_ATTR_SEC_KEY], nl802154_key_policy, info->extack))
return -EINVAL;

if (ieee802154_llsec_parse_key_id(attrs[NL802154_KEY_ATTR_ID], &id) < 0)
--
2.30.2

2021-04-05 00:38:33

by Alexander Aring

Subject: Re: [PATCH] net: fix NULL ptr dereference in nl802154_del_llsec_key

Hi,

On Sat, 3 Apr 2021 at 11:18, Pavel Skripkin <[email protected]> wrote:
>
> syzbot reported NULL ptr dereference in nl802154_del_llsec_key()[1]
> The problem was in case of info->attrs[NL802154_ATTR_SEC_KEY] == NULL.
> nla_parse_nested_deprecated()[2] doesn't check this condition before calling
> nla_len()[3]
>

this is already fixed in the same way just not in net yet.

- Alex